Among the materials for thermistor usable at elevated temperatures, there have hitherto been employed (a) a material based on a dorundum type crystal structure, mainly composed of Al.sub.2 O.sub.3 and Cr.sub.2 O.sub.3, as disclosed for example in JP Patent Kokai Publication JP-A 50-118294, (b) a material based on a spinel type crystal structure, mainly composed of MgAl.sub.2 O.sub.4, MgCr.sub.2 O.sub.4 and MgFe.sub.2 O.sub.4, as disclosed for example in JP Patent Kokai Publication JP-A 49-63995, (c) a material mainly composed of ZrO.sub.2, stabilized mainly with Y.sub.2 O.sub.3 etc., as disclosed for example in "Nainen Kikan" (Internal Combustion Engine), vol. 30, No. 8, page 98, and (d) a material mainly composed of a compound having a perovskite type crystal structure, exhibiting a high melting point and electrical conductivity, such as a material having a La(Al.sub.1-x Cr.sub.x)O.sub.3 based composition, as disclosed in, for example, JP Patent Kokai Publication JP-A 51-108298, a material having a thin film of LaCrO.sub.3 on an insulating substrate, as disclosed for example in JP Patent Kokai Publication JP-A 61-161701, or a material comprising a mixture of LaCrO.sub.3 and MgAl.sub.2 O.sub.4, as disclosed for example in JP Patent Kokai Publications JP-A 51-95297 and JP-A 51-23691.